" It was bad. I don't want to go into details but I drank a lot and it was daily - I mean nightly," he told Heat. "I can point to many scenes [in Harry Potter] where I'm just gone. Dead behind the eyes.

"I loved the fact I suddenly could talk to people and feel so entertaining and so interesting. But after a while, you're living under such a cloud of shame about what you've done and the dread of who you might see, what you might have said to them, what you might have done with them.

"You either have to change something or give into that shame and I wasn't prepared to do that at 21."

Radcliffe also dismissed suggestions that growing up in the spotlight had sparked his drink problem, arguing: "I think it would have happened anyway. I think it's just in me."